Marama Davidson is defending fellow Green Party co-leader James Shaw after he was accused of being too centrist.
Jack McDonald, who was ranked 11th on the party list during the last election, is removing his name from candidacy in Te Tai Hauauru and will not be seeking re-election as the Greens' policy co-convenor, citing the party's centrist shift under Mr Shaw as one of the reasons.
At the party's AGM in Dunedin at the weekend, Mr Shaw took a swing at National Party leader Simon Bridges, branding him a climate change denier.
"The politicians and their allies, who are the new climate deniers, are driven by something even more dangerous, short-term, calculated self-interest."
Mr Bridges said he is not a denier and said the accusation showed Mr Shaw was under pressure.
But they were exactly the sort of comments Jack McDonald wished he would see more of from Mr Shaw.
"That is speaking the truth and being bold and unapologetic and that's what voters actually respond to, in my view, they don't respond to timidity and moderation."
Among Mr McDonald's reasons for stepping down was that he believed the party was becoming more politically central under Mr Shaw.
"The Zero Carbon Act is an example, I think, of where James Shaw could have been stronger. He admittedly publicly that he gave concessions to the National Party without even getting their guaranteed support for the bill.
"So I think there are a number of issues to where his approach to politics are different to what I think the Greens should be and what the Greens were in terms of our roots."
But co-leader Marama Davidson does not agree the party is becoming more centrist.
"James and I are working hard every single day to put up transformational changes, as well as the work that we've already done - but we agree with our members that we want faster and stronger change and that's our priority."
Mr Shaw told Morning Report the concessions on the bill were aimed at ensuring bipartisan support so the legislation would survive multiple changes of government.
"This was always going to be difficult in our first term of government ever, moving into a situation where we've got to make compromises... because under MMP there are many parties in Parliament and they've all got different views.
"The very clear signal we've had both from environmental movement and, actually, from corporate New Zealand is that they desperately want bipartisan support for the bill to make sure that there is that long-term stability.
"We're trying to create a framework that's going to survive over multiple decades, that does involve some compromises."
Asked if the Greens would compromise on what is shaping up as the most contentious part of the Bill - the methane targets, which are being widely opposed by the dairy industry - he said the numbers were almost identical to those provided by the industry-led Biological Emissions Reference Group set up by the previous National-led government.
"Here's the thing, you would have to prove that any change to the target would meet the requirement of living within one and a half degrees of global warming and I haven't seen any science yet that suggests you could do less than what is required for the rest of the planet and do that."
Mr Shaw said for the most part members were on board with the path the party was taking.
"They're really pleased that we're in government, it's certainly a lot better than the alternative in terms of the progress that we've been able to make and we also know that people want us to go faster, and to go further and at the same time they recognise that there are constraints in an MMP government."
Other party members RNZ spoke to were sympathetic to the constraints of a coalition government, but agreed they would like to see more action on matters like climate change.
The Green Party wants to continue as part of the government after next year's election and there's certain to be more soul-searching about what further sacrifices the party and its members might have to make.